CN114264882B

CN114264882B - Equivalent parameter measuring method and device of ultrasonic transducer and controller

Info

Publication number: CN114264882B
Application number: CN202111603303.9A
Authority: CN
Inventors: 盛龙; 闵建君
Original assignee: Shenzhen Taida Intelligent Equipment Co ltd
Current assignee: Shenzhen Taida Intelligent Equipment Co ltd
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2022-09-02
Anticipated expiration: 2041-12-24
Also published as: CN114264882A

Abstract

The application relates to an equivalent parameter measuring method and device of an ultrasonic transducer and a controller. The method comprises the following steps: acquiring an initial frequency sweep interval, and sweeping the frequency of the ultrasonic transducer by a first step length in the initial frequency sweep interval to acquire a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size; sweeping the frequency of the ultrasonic transducer by a second step length in a target frequency sweeping interval to obtain a first feedback electrical parameter set of the ultrasonic transducer; the target sweep frequency interval is a frequency band between the first half-power point and the second half-power point; and obtaining the equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set. By adopting the method, the time consumption for measuring the equivalent parameters of the ultrasonic transducer can be shortened, and the rapid measurement can be realized.

Description

Equivalent parameter measuring method and device of ultrasonic transducer and controller

Technical Field

The present disclosure relates to the field of ultrasonic transducer technology, and in particular, to an equivalent parameter measuring method, an equivalent parameter measuring device, and a controller for an ultrasonic transducer.

Background

In recent years, with the development of ultrasonic technology, ultrasonic application technology has penetrated the aspects of life. For example, the ultrasonic bone knife can be applied to ultrasonic physiotherapy instruments and ultrasonic bone knives in the medical field, mechanical arm joints and clamping devices in the intelligent robot field, ultrasonic bonding technology in the semiconductor field and the like. In the devices or components listed above, the core components are all ultrasonic transducers, i.e. a device which can convert electrical energy into mechanical energy, thereby generating ultrasonic vibration and meeting production requirements.

For the ultrasonic transducers required in different fields, the ultrasonic transducers are different in material, structure and the like, and therefore, the ultrasonic transducers exhibit different characteristics. In order to realize stable driving of the ultrasonic transducers, each ultrasonic transducer needs to be accurately modeled, and a proper frequency band is selected according to a modeling result to drive the ultrasonic transducers, so that the ultrasonic transducers can work in an optimal state, and further heating and energy loss are reduced.

Ultrasonic transducer frequency sweep identification is an effective method for obtaining an ultrasonic transducer equivalent mathematical model, and is a prerequisite for ultrasonic vibration application. In the process of frequency sweeping identification, a driving signal with corresponding frequency can be output to the ultrasonic transducer, and an equivalent mathematical model of the ultrasonic transducer is established according to data such as current, voltage and phase fed back by the ultrasonic transducer, so that impedance characteristics, phase characteristics and the like in the equivalent mathematical model are close to actual measurement characteristics of the ultrasonic transducer.

At present, an apparatus for performing ultrasonic transducer frequency sweep identification is mainly an impedance analyzer, which takes a BVD (Butterworth-Van Dyke) model as a theoretical model. The impedance analyzer performs frequency sweeping through a frequency sweeping algorithm in the impedance analyzer, analyzes data obtained by frequency sweeping by adopting a circuit analysis rule to calculate the impedance characteristic, the phase characteristic and other effect parameters of the BVD model, further establishes an equivalent circuit model of the ultrasonic transducer based on the BVD model and provides a basis for subsequent stable driving. However, the impedance analyzer has a problem of consuming too much time in determining the equivalent parameters.

Disclosure of Invention

Therefore, it is necessary to provide an equivalent parameter measuring method, an equivalent parameter measuring device, and a controller for an ultrasonic transducer to reduce the time consumption for determining equivalent parameters of the ultrasonic transducer and achieve fast measurement of the equivalent parameters.

In a first aspect, the application provides a method for measuring equivalent parameters of an ultrasonic transducer. The method comprises the following steps:

acquiring an initial frequency sweep interval, and sweeping the frequency of the ultrasonic transducer by a first step length in the initial frequency sweep interval to acquire a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size;

sweeping the frequency of the ultrasonic transducer by a second step length in a target frequency sweeping interval to obtain a first feedback electrical parameter set of the ultrasonic transducer; the target sweep frequency interval is a frequency band between the first half-power point and the second half-power point;

and obtaining the equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set.

In a second aspect, the application further provides an equivalent parameter measuring device of the ultrasonic transducer. The device comprises a driving signal generation module and a control module which are connected in sequence, wherein the driving signal generation module and the control module are both used for connecting an ultrasonic transducer;

the driving signal generation module is used for outputting a corresponding driving signal to the ultrasonic transducer according to the received frequency control signal and amplitude control signal;

the control module is used for acquiring an initial frequency sweep interval, outputting a corresponding frequency control signal and an amplitude control signal to the driving signal generation module according to the initial frequency sweep interval and a first step length, so as to sweep the frequency of the ultrasonic transducer in the initial frequency sweep interval by the first step length, and acquiring a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size;

the control module is further configured to output a corresponding frequency control signal and an amplitude control signal to the driving signal generation module according to a target frequency sweep interval and a second step length, so as to sweep the frequency of the ultrasonic transducer within the target frequency sweep interval by the second step length and obtain a first feedback electrical parameter set of the ultrasonic transducer; obtaining equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set; and the target frequency sweeping interval is a frequency band between the first half-power point and the second half-power point.

In a third aspect, the application further provides an equivalent parameter measuring device of the ultrasonic transducer. The device comprises:

the device comprises a half-power point acquisition module, a frequency sweep processing module and a frequency sweep processing module, wherein the half-power point acquisition module is used for acquiring an initial frequency sweep interval and sweeping the frequency of the ultrasonic transducer by a first step length in the initial frequency sweep interval so as to acquire a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size;

the first feedback electrical parameter set acquisition module is used for sweeping the frequency of the ultrasonic transducer by a second step length in a target frequency sweeping interval so as to acquire a first feedback electrical parameter set of the ultrasonic transducer; the target sweep frequency interval is a frequency band between the first half-power point and the second half-power point;

and the equivalent parameter acquisition module is used for acquiring the equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set.

In a fourth aspect, the present application further provides a controller. The controller comprises a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program:

In a fifth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of:

In a sixth aspect, the present application further provides a computer program product. The computer program product comprising a computer program which when executed by a processor performs the steps of:

The method, the device, the controller, the computer storage medium and the computer program product for measuring the equivalent parameters of the ultrasonic transducer acquire an initial frequency sweep interval, sweep the frequency of the ultrasonic transducer by a first step length which is increased progressively in the initial frequency sweep interval so as to acquire a first half-power point and a second half-power point of the ultrasonic transducer, and use a frequency band between the first half-power point and the second half-power point as a target frequency sweep interval. The method and the device have the advantages that the frequency of the ultrasonic transducer is swept within a target frequency sweeping interval by the second step length, so that a first feedback electrical parameter set of the ultrasonic transducer is obtained, and the equivalent parameters of the ultrasonic transducer are obtained according to the first feedback electrical parameter set. Therefore, the method can realize the quick positioning of the half-power point, can quickly determine the target frequency sweeping interval associated with the equivalent parameter measurement of the ultrasonic transducer, overcomes the problem that the traditional algorithm needs to carry out full-band search, can further shorten the time consumption of the equivalent parameter measurement of the ultrasonic transducer, and realizes quick measurement.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the description of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the description below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a circuit diagram of a BVD model in an embodiment;

FIG. 2 is a schematic flow chart of an equivalent parameter measurement method of an ultrasonic transducer according to an embodiment;

FIG. 3 is a schematic diagram illustrating a process of obtaining equivalent parameters according to a feedback parameter set in an embodiment;

FIG. 4 is a schematic flow chart of an embodiment for performing admittance circle fitting using a least squares fitting algorithm;

FIG. 5 is one of the flow diagrams for obtaining the first half-power point and the second half-power point in one embodiment;

FIG. 6 is a schematic diagram illustrating a process of determining frequency points of an initial frequency sweep in an embodiment;

FIG. 7 is a second flowchart illustrating a process of obtaining a first half-power point and a second half-power point according to an embodiment;

FIG. 8 is a second schematic flowchart of an equivalent parameter measurement method of an ultrasonic transducer according to an embodiment;

FIG. 9 is a graph of a comparison of the measurements of the present application with the impedance analyzer measurements in one embodiment;

FIG. 10 is a block diagram showing an equivalent parameter measuring apparatus of an ultrasonic transducer according to an embodiment;

FIG. 11 is a second block diagram of an equivalent parameter measuring device of an ultrasonic transducer according to an embodiment.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms "first," "second," and the like as used herein may be used herein to describe various features, but these features are not limited by these terms. The "connection" in the following embodiments is understood as "electrical connection", "communication connection", or the like if the connected circuits, modules, units, or the like have electrical signals or data transmission therebetween.

As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," or "having," and the like, specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.

As described in the background, the prior art has a problem of consuming too much time in determining equivalent parameters. The inventor researches and discovers that the problem is caused because the frequency sweep algorithm adopted by the mainstream impedance analyzer is a common sweep algorithm, namely, the frequency band to be swept is subdivided into a certain number of sampling points, the frequency of the driving signal is changed from low frequency to high frequency or from high frequency to low frequency, the sweep interval is continuously reduced according to the feedback electrical parameters of the ultrasonic transducer to complete the frequency sweep, and the equivalent parameters of the BVD model are obtained through calculation according to the feedback electrical parameters of the ultrasonic transducer. Therefore, the time consumption of the prior art is generally long, and the ultrasonic transducer cannot be calibrated in a short clearance.

In addition, with the improvement of the technological level, the control requirements for the ultrasonic transducer in the actual industrial field are higher and higher. However, impedance analyzers in the market are all frequency sweep identification under low voltage, that is, in the process of frequency sweep identification, the impedance analyzer excites the ultrasonic transducer through a driving signal with lower voltage, and frequency sweep of the ultrasonic transducer is realized by adjusting the frequency of the low-voltage driving signal, so that equivalent parameters are obtained. However, the same ultrasonic transducer has nonlinear effects such as amplitude-frequency effect, intermodulation effect and frequency offset effect under different voltages, and if actual driving and production are performed according to performance data obtained by low-voltage frequency sweep identification, the whole system cannot work near a resonance point, so that the problem of low efficiency is caused, and the ultrasonic transducer may be damaged.

In order to solve the foregoing problems, the present application provides an equivalent parameter measurement method, an equivalent parameter measurement device, and a controller for an ultrasonic transducer, so as to reduce time consumption for determining equivalent parameters of an ultrasonic transducer and achieve rapid measurement of equivalent parameters. In some embodiments, the present application may also more accurately identify equivalent parameters of the ultrasonic transducers.

The BVD model is fully described for the properties of the ultrasonic transducer, and the principle is simple, so the BVD model is taken as a theoretical model, and the equivalent parameters of the ultrasonic transducer are acquired through the following embodiments to establish an equivalent circuit model corresponding to the ultrasonic transducer. In particular, the BVD model may be as shown in fig. 1. Wherein, R0 is a static resistor, and since the resistance value is generally very large, the branch in which R0 is located can be regarded as an open circuit. C0 is a static capacitor, and the branch in which C0 is located is a static branch. L1 is dynamic inductance, C1 is dynamic capacitance, R1 is dynamic resistance, and the branch where L1, C1 and R1 are located is a dynamic branch.

In one embodiment, the present application provides a method of measuring an equivalent parameter of an ultrasonic transducer. In one embodiment, the method may be implemented by a controller or a plurality of controllers. In another embodiment, the method may be implemented by a circuit arrangement. The one or more controllers, or the circuit device, may have voltage output, adjustable output voltage frequency, adjustable output voltage amplitude, electrical parameter acquisition, and data processing capabilities.

As shown in fig. 2, the method for measuring equivalent parameters of an ultrasonic transducer may specifically include the following steps:

s200, acquiring an initial frequency sweep interval, and sweeping the frequency of the ultrasonic transducer by a first step length in the initial frequency sweep interval to acquire a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size.

Wherein the initial sweep interval may be an approximate frequency range for determining the resonant frequency of the ultrasonic transducer. Considering the individual characteristics of each ultrasonic transducer, even if the ultrasonic transducers are produced in the same batch, the resonant frequencies of each ultrasonic transducer in the batch are difficult to be completely identical, and only the approximate frequency range of each resonant frequency, namely the initial sweep interval, can be determined. In the practical application process, the specific resonant frequency of each ultrasonic transducer can be determined according to the initial frequency sweep interval, so that stable driving can be realized in subsequent application.

The half-power point is a frequency point corresponding to the fact that the gain of the ultrasonic transducer is reduced by 3dB compared with the maximum gain of the ultrasonic transducer under the condition that the amplitude of an input signal is kept unchanged, namely a-3 dB point. Generally, the ultrasonic transducer has two half-power points in the initial sweep interval, that is, the gain of the ultrasonic transducer is reduced by 3dB at two different frequencies, that is, the first half-power point and the second half-power point in each embodiment.

The incremental step length means that the step length is gradually increased, that is, in the process of frequency sweeping according to the first step length, for frequency point changes of frequency sweeping twice, the frequency point change amount of the previous time is smaller than the frequency point change amount of the next time. For example, in the next 3 frequency sweeps, the sweep frequency points are frequency point a, frequency point B and frequency point C, and the absolute value of the difference between frequency point a and frequency point B is smaller than the absolute value of the difference between frequency point B and frequency point C.

Specifically, after an initial frequency sweep interval with a large range is obtained, the ultrasonic transducer is swept once within the initial frequency sweep interval by an increasing first step length, that is, a driving signal can be applied to the ultrasonic transducer to excite the ultrasonic transducer to work, and the frequency of the driving signal is adjusted by the increasing first step length to obtain a first half-power point and a second half-power point of the ultrasonic transducer within the initial frequency sweep interval. Thus, the quick positioning of the half-power point can be realized.

It is understood that the frequency of the driving signal can be changed from a high frequency to a low frequency, and can also be changed from a low frequency to a high frequency, which is not particularly limited in this application.

S300, sweeping the frequency of the ultrasonic transducer by a second step length in a target frequency sweeping interval to obtain a first feedback electrical parameter set of the ultrasonic transducer; and the target frequency sweeping interval is a frequency band between the first half-power point and the second half-power point.

The first feedback electrical parameter set is combined to be a feedback electrical parameter of the ultrasonic transducer during the frequency sweeping process of the ultrasonic transducer according to the target frequency sweeping interval, and the feedback electrical parameter can be voltage, current and/or phase and the like.

Specifically, for an ultrasonic transducer, it may have multiple resonant frequencies, but not every resonant frequency may be used in practical applications. In practical applications, the driving of the ultrasonic transducer needs to be realized through a resonance frequency falling within a desired frequency band. The performance of the ultrasonic transducer in the desired frequency band is related to its equivalent parameters. In the application, the first half-power point and the second half-power point of the ultrasonic transducer are quickly positioned in step S210, the frequency band between the first half-power point and the second half-power point is used as the expected frequency band, and the frequency sweep is performed on the ultrasonic transducer for the second time in the frequency band by the second step length, so that the feedback electrical parameters of the ultrasonic transducer in the expected frequency band, namely the first feedback electrical parameter set, can be obtained.

It is understood that the second step size can be determined according to actual conditions (such as measurement time requirement, accuracy requirement, etc.), and the application is not limited thereto. In one embodiment, the second step size may be an increasing step size or a decreasing step size. In another embodiment, the second step size may also be fixed.

And S400, obtaining equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set.

Specifically, after the feedback electrical parameters of the ultrasonic transducer in the target sweep frequency interval are obtained, the equivalent parameters of the ultrasonic transducer can be calculated according to the feedback electrical parameters.

In the equivalent parameter measuring method of the ultrasonic transducer, the frequency sweeping is carried out on the ultrasonic transducer by the first step length which is increased progressively in the initial frequency sweeping interval by obtaining the initial frequency sweeping interval so as to obtain the first half-power point and the second half-power point of the ultrasonic transducer, and the frequency band between the first half-power point and the second half-power point is used as the target frequency sweeping interval. The method and the device have the advantages that the frequency of the ultrasonic transducer is swept within a target frequency sweeping interval by the second step length, so that a first feedback electrical parameter set of the ultrasonic transducer is obtained, and the equivalent parameters of the ultrasonic transducer are obtained according to the first feedback electrical parameter set. Therefore, the method can realize the quick positioning of the half-power point, can quickly determine the target frequency sweeping interval associated with the measurement of the equivalent parameters of the ultrasonic transducer, overcomes the problem that the traditional algorithm needs to search in a full frequency band, can shorten the time consumption for measuring the equivalent parameters of the ultrasonic transducer, and realizes quick measurement.

In one embodiment, the first feedback electrical parameter set includes first feedback electrical parameters of the ultrasonic transducer at each target frequency sweep point, and each target frequency sweep point is a frequency sweep point determined according to the target frequency sweep interval and the second step length.

As shown in fig. 3, the step of obtaining the equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set includes:

s410, for each target frequency sweeping frequency point, respectively determining an admittance imaginary part value and an admittance real part value of the ultrasonic transducer at the target frequency sweeping frequency point according to a first feedback electrical parameter of the ultrasonic transducer at the target frequency sweeping frequency point;

and S420, carrying out admittance circle fitting according to the admittance imaginary part values and the admittance real part values corresponding to the target frequency sweeping points, and determining equivalent parameters based on the admittance circle parameters obtained by fitting.

Specifically, in the process of sweeping the frequency of the ultrasonic transducer by the second step length in the target frequency sweeping interval, each target frequency sweeping frequency point in the target frequency sweeping interval can be determined according to the second step length, and the signal frequency of the driving signal applied to the ultrasonic transducer is adjusted according to each target frequency sweeping frequency point, so as to obtain a first feedback electrical parameter of the ultrasonic transducer at each target frequency sweeping frequency point.

For each target frequency sweeping frequency point, under the condition that the first feedback electrical parameter corresponding to the target frequency sweeping frequency point is obtained, the admittance imaginary part value and the admittance real part value of the ultrasonic transducer under the target frequency sweeping frequency point can be determined according to the first feedback electrical parameter corresponding to the target frequency sweeping frequency point. After the admittance imaginary part value and the admittance real part value corresponding to each target sweep frequency point are obtained, admittance circle fitting can be carried out according to the admittance imaginary part value and the admittance real part value so as to obtain admittance circle parameters, and the equivalent parameters of the ultrasonic transducer are determined according to the admittance circle parameters.

It is to be understood that the present application may employ any algorithm disclosed in the prior art for admittance circle fitting, and the present application is not particularly limited thereto. In one embodiment, the method and the device can adopt a least square fitting algorithm to process the admittance imaginary part value and the admittance real part value corresponding to each target frequency sweeping point so as to perform admittance circle fitting, thereby simplifying the calculation process of admittance circle fitting on the basis of ensuring the measurement accuracy of equivalent parameters and further realizing rapid measurement. In one example, as shown in fig. 4, the step of performing admittance circle fitting by using a least square fitting algorithm and determining equivalent parameters based on the admittance circle parameters obtained by the fitting may include:

s422, constructing an error function;

s424, the error function calculates the partial derivative;

s426, acquiring admittance circle parameters including but not limited to the center coordinates of the admittance circle and the radius of the admittance circle;

and S428, calculating the equivalent parameters of the BVD.

In this embodiment, admittance circle fitting is performed by using admittance data of a half-power point interval (i.e., a target frequency sweep interval), and an equivalent parameter of the ultrasonic transducer is determined according to the admittance circle parameter obtained by fitting, so that possible interference in the left half of the admittance circle can be reduced, and further, the measurement accuracy of the equivalent parameter can be improved.

In one embodiment, the admittance circle parameters include a center ordinate of the admittance circle and a radius of the admittance circle, and the equivalent parameters include a static capacitance value, a dynamic inductance value, and a dynamic resistance value.

The step of determining equivalent parameters based on the admittance circle parameters obtained by fitting includes:

determining the series resonance frequency of the ultrasonic transducer according to the first half-power point and the second half-power point;

determining a static capacitance value, a dynamic inductance value and a dynamic resistance value respectively based on the following expressions:

wherein R is ₁ Is a dynamic resistance value, C ₀ Is a static capacitance value, L ₁ Is a dynamic inductance value, C ₁ Is a dynamic capacitance value, r is a radius, y is a center ordinate, f _s Is the series resonance frequency, f ₂ Is the second half power point, f ₁ Is the first half-power point.

Specifically, the present application may determine a series resonant frequency of the ultrasonic transducer based on the first half power point and the second half power point. In one embodiment, the series resonant frequency can be an average of the first half power point and the second half power point.

After the series resonance frequency is obtained, respectively calculating a static capacitance value, a dynamic inductance value and a dynamic resistance value based on the formula according to the series resonance frequency, the first half-power point, the second half-power point, the longitudinal coordinate of the center of the admittance circle and the radius of the admittance circle, and completing the measurement of the equivalent parameters of the ultrasonic transducer.

In this embodiment, admittance data of the half-power point interval are used to perform admittance circle fitting, so that possible interference in the left half of the admittance circle can be reduced. And the fitting data comprises series resonance frequency, so that the reconstructed admittance circle is close to the actual working condition, and the measurement accuracy of the equivalent parameters can be improved.

In one embodiment, the second step size may be a fixed step size, i.e., the second step size may be fixed and constant. In other words, when the ultrasonic transducer is swept within the target sweep interval, the sweep may be performed with a fixed step size. Therefore, each first feedback electrical parameter which is uniformly distributed can be obtained, and the fitting accuracy of the admittance circle can be further improved, so that the measurement accuracy of the equivalent parameter can be improved.

It is understood that the specific value of the second step can be determined according to practical situations, and the application does not limit the specific value. In one example, the second step size may be 1 Hz.

In one embodiment, as shown in fig. 5, the step of sweeping the ultrasonic transducer by a first step size within an initial sweep interval to obtain a first half power point and a second half power point of the ultrasonic transducer includes:

s210, determining each initial frequency sweeping frequency point according to the initial frequency sweeping interval and the first step length;

s220, sweeping the frequency of the ultrasonic transducer based on each initial sweeping frequency point, and acquiring an admittance imaginary part value of the ultrasonic transducer under each initial sweeping frequency point;

s230, determining the initial frequency sweeping frequency point corresponding to the minimum value in each admittance imaginary part value as a first target frequency, and determining the initial frequency sweeping frequency point corresponding to the maximum value in each admittance imaginary part value as a second target frequency;

and S240, determining the smaller value of the first target frequency and the second target frequency as a first half-power point, and determining the larger value of the first target frequency and the second target frequency as a second half-power point.

Specifically, in the process of one frequency sweep, each initial frequency sweep frequency point can be determined according to the initial frequency sweep interval and the incremental first step length, and the signal frequency of the driving signal applied to the ultrasonic transducer is adjusted according to each initial frequency sweep frequency point, so as to obtain the admittance imaginary part value of the ultrasonic transducer at each initial frequency sweep frequency point. After each initial frequency sweeping frequency point is obtained, the maximum value and the minimum value in each admittance imaginary part value can be searched, the smaller value of the initial frequency sweeping frequency point corresponding to the maximum value and the initial frequency sweeping frequency point corresponding to the minimum value is determined as a first half-power point, and the larger value of the initial frequency sweeping frequency point corresponding to the maximum value and the initial frequency sweeping frequency point corresponding to the minimum value is determined as a second half-power point. Therefore, two half-power points in the initial frequency sweeping interval are indirectly obtained by searching the maximum value and the minimum value in each admittance imaginary part value. Compared with the traditional method for searching the maximum value in the admittance real part values corresponding to each initial frequency sweeping frequency point, the method can simplify the search algorithm of the half-power point, further reduce the test time consumption and realize the rapid measurement of the equivalent parameters.

In one embodiment, the step of sweeping the frequency of the ultrasonic transducer based on each initial frequency sweeping point and acquiring the admittance imaginary part value of the ultrasonic transducer at each initial frequency sweeping point comprises:

sweeping the frequency of the ultrasonic transducer based on each initial frequency sweeping frequency point, and collecting a second feedback electrical parameter of the ultrasonic transducer under each initial frequency sweeping frequency point; the second feedback electrical parameters comprise an initial voltage effective value, an initial current effective value and a phase of the ultrasonic transducer under the corresponding initial frequency sweeping frequency point;

for each initial frequency sweeping frequency point, filtering the initial voltage effective value to obtain a target voltage effective value, and filtering the initial current effective value to obtain a target current effective value; and determining the admittance imaginary part value of the ultrasonic transducer at the initial frequency sweeping frequency point according to the following formula:

wherein G is _img To admittance imaginary values, I _rms Is the effective value of the target current, U _rms The target voltage effective value is shown, and theta is the phase.

Specifically, in the process of determining the admittance imaginary part value of the ultrasonic transducer at each initial frequency sweeping point, the ultrasonic transducer can be swept through each initial frequency sweeping point, that is, the signal frequency of the driving signal applied to the ultrasonic transducer is respectively adjusted to each initial frequency sweeping point, and a second feedback electrical parameter of the ultrasonic transducer at each initial frequency sweeping point is obtained. The second feedback electrical parameter includes an initial voltage effective value, an initial current effective value and a phase.

For each initial frequency sweeping point, the admittance imaginary part value of the ultrasonic transducer under the initial frequency sweeping point can be determined according to the following process:

filtering the initial voltage effective value corresponding to the initial frequency sweeping frequency point to obtain a target voltage effective value; filtering an initial current effective value corresponding to the initial frequency sweeping frequency point to obtain a target current effective value; and calculating the admittance imaginary part value of the ultrasonic transducer under the initial frequency sweeping frequency point based on the admittance imaginary part value calculation formula according to the target current effective value, the target voltage effective value and the phase corresponding to the initial frequency sweeping frequency point. And for each initial frequency sweeping point, the admittance imaginary part value of the ultrasonic transducer at each initial frequency sweeping point is determined according to the process, so that the first half-power point and the second half-power point can be determined according to the admittance imaginary part values.

It is understood that the present application may filter the initial voltage effective value and the initial current effective value by the same or different filtering methods and/or filtering times, respectively, to obtain the target voltage effective value and the target current effective value. Meanwhile, the filtering algorithm can be realized by adopting any mode and any principle in the prior art, and the filtering algorithm is not particularly limited in the application. In one example, the present application may implement filtering of the initial voltage effective value and the initial current effective value by using one mean filtering and one median filtering, that is, the initial voltage effective value is sequentially subjected to one mean filtering process and one median filtering process to obtain the target voltage effective value. The initial current effective value is sequentially subjected to primary mean filtering processing and primary median filtering processing to obtain a target current effective value

In this embodiment, the initial voltage effective value and the initial current effective value in the second feedback electrical parameter are filtered to obtain a target voltage effective value and a target current effective value, so that the accuracy of the voltage effective value and the current effective value can be improved. Therefore, the admittance imaginary part value calculated based on the target voltage effective value and the target current effective value can be more accurate.

In an embodiment, as shown in fig. 6, the step of determining each initial frequency sweeping frequency point according to the initial frequency sweeping interval and the first step size includes:

s212, confirming the first threshold frequency of the initial frequency sweep interval as the current initial frequency sweep frequency point;

s214, increasing the first step length according to a preset proportion, and determining a next initial frequency sweeping frequency point according to the increased first step length and the current initial frequency sweeping frequency point;

and S216, taking the next initial frequency sweeping frequency point as the current initial frequency sweeping frequency point, and entering the step S214 until the next initial frequency sweeping frequency point exceeds the initial frequency sweeping interval, or acquiring a first half-power point and a second half-power point.

Wherein, the first threshold frequency may be an upper limit value or a lower limit value of the initial frequency sweep interval, for example, when the initial frequency sweep interval is [ f ] _d ，f _e ]The first threshold frequency may be f _d Or f _e 。

Specifically, the method and the device can confirm the first threshold frequency of the initial frequency sweeping interval as the current initial frequency sweeping frequency point, increase the first step length according to the preset proportion, and determine the next initial frequency sweeping frequency point according to the increased first step length and the current initial frequency sweeping frequency point. And under the condition that the next initial frequency sweeping frequency point does not exceed the initial frequency sweeping interval and two half-power points are not obtained, taking the next initial frequency sweeping frequency point as the current frequency sweeping frequency point, and increasing the current first step length according to a preset proportion, namely delta f ═ delta f x (1+ a), wherein the first step length is obtained after the delta f' is increased, the delta f is the current first step length, and the a is the preset proportion. And determining the next initial frequency sweeping frequency point relative to the current initial frequency sweeping frequency point according to the increased first step length and the current initial frequency sweeping frequency point. And the steps are executed in a circulating manner until the determined next initial frequency sweeping frequency point exceeds the initial frequency sweeping interval, and two half-power points of the ultrasonic transducer are obtained. In one example, "exceeding the initial sweep interval" can be greater than an upper limit of the initial sweep interval or less than a lower limit of the initial sweep interval.

It is understood that the preset ratio can be determined according to practical situations, and the application is not limited thereto specifically. In one example, the preset ratio may be 10%, i.e. the first step size is controlled to be continuously increased at a rate of 10%.

With the first threshold frequency f _d For example, the present application may refer to f _d Confirming as the current initial sweep frequency point, and increasing the first step length according to a preset proportion to obtain the increased first step length delta f _A . According to the increased first step length deltaf _A And f _d Determining the frequency point f of the next initial sweep frequency _g . Judgment of f _g Whether or not it is greater than f _e Or whether two half-power points have been acquired. If not, f will be confirmed _g The frequency point of the current initial sweep frequency is increased by a first step length delta f according to a preset proportion _A To obtain a first step length Δ f _B . According to the increased first step length deltaf _B And f _g Determining the frequency point f of the next initial sweep frequency _h . Judgment of f _h Whether or not it is greater than f _e Or whether two half-power points have been acquired. If not, f is _e Determining the frequency point as the current initial frequency sweep frequency point, and determining the next initial frequency sweep frequency point until the determined next initial frequency sweep frequency point is more than f _e Or two half-power points of the ultrasonic transducer have been acquired.

In one embodiment, in order to avoid the accuracy of the determined first half-power point and the second half-power point from being reduced due to the excessive first step length, an upper limit value of the first step length can be set, i.e. the maximum value of the first step length is the upper limit value. And if the value of the first step length after the increment is smaller than the upper limit value, determining the next initial frequency sweeping frequency point according to the first step length after the increment. And if the value of the first step length after the increment is larger than or equal to the upper limit value of the first step length, determining the next initial frequency sweeping frequency point according to the upper limit value of the first step length. It is understood that the upper limit value of the first step size can be determined according to practical situations, and the application does not specifically limit this. In one example, it may be 10% of the initial sweep interval.

In one example, the application may determine the first half-power point and the second half-power point according to the steps shown in fig. 7, and specifically includes the steps of:

s502, increasing the first step length according to a preset proportion, and determining a next initial frequency sweeping frequency point according to the increased first step length and the current initial frequency sweeping frequency point;

s504, sweeping the frequency of the ultrasonic transducer based on the next initial frequency sweeping point, and acquiring an admittance imaginary part value of the ultrasonic transducer under the next initial frequency sweeping point;

s506, calculating a second derivative of the admittance imaginary part value;

s508, judging whether an extreme value condition is met according to the calculated second derivative, if not, entering S510, and if so, entering S512;

s510, taking the next initial frequency sweeping frequency point as a current initial frequency sweeping frequency point, and entering S502;

s512, taking the next initial frequency sweeping frequency point as a half-power point;

and S514, judging whether two half-power points are obtained or not, if not, entering S510, and if so, ending.

In one embodiment, a swept frequency drive voltage is acquired; the sweep driving voltage is determined based on the actual driving voltage of the ultrasonic transducer.

The method for sweeping the frequency of the ultrasonic transducer by a first step length in an initial sweep frequency interval comprises the following steps: and based on the sweep frequency driving voltage, sweeping the frequency of the ultrasonic transducer by a first step length in an initial sweep frequency interval.

And sweeping the ultrasonic transducer by a second step length in a target sweep interval, wherein the step comprises the following steps of: and based on the sweep frequency driving voltage, sweeping the frequency of the ultrasonic transducer by a second step length in the target sweep frequency interval.

Specifically, the method and the device can use the actual driving voltage used in the actual driving production process of the ultrasonic transducer as the sweep driving voltage used in the equivalent parameter measurement, so that the measured equivalent parameter can reflect the impedance characteristic and the phase characteristic of the ultrasonic transducer in the actual driving production. Compared with an experience approximation method used by a traditional ultrasonic transducer identification algorithm, the theoretical basis of the method is more sufficient, the impedance characteristic, the phase characteristic and the like of the established equivalent circuit model are more in line with the actual driving condition, the descriptiveness is more sufficient, therefore, a more accurate basis can be provided for the subsequent driving control of the ultrasonic transducer, and the use efficiency of the ultrasonic transducer is effectively improved.

In an example, the equivalent parameter measurement method of the present application may be as shown in fig. 8, and specifically includes the following steps:

and S602, acquiring an initial frequency sweep interval.

And S604, determining the next initial frequency sweeping frequency point according to the incremental first step length and the current initial frequency sweeping frequency point. Specifically, the first step size may be controlled to be continuously enlarged at a rate of 10%, which is at most 10% of the initial sweep interval.

And S606, acquiring second feedback electrical parameters of the ultrasonic transducer at the next initial frequency sweeping point, wherein the second feedback electrical parameters comprise an initial voltage effective value, an initial current effective value and a phase of the ultrasonic transducer at the next initial frequency sweeping point.

And S608, judging whether the next initial sweep frequency point is the half-power point of the ultrasonic transducer according to the second feedback electrical parameter, if so, entering S610, and if not, entering S604.

Specifically, the initial voltage effective value is subjected to an average filtering and a median filtering to obtain a target voltage effective value. And carrying out primary mean filtering and primary median filtering on the initial current effective value to obtain a target current effective value. And calculating the admittance imaginary value of the ultrasonic transducer at the next initial frequency-sweeping frequency point according to the following formula:

By searching the maximum value point and the minimum value point of the admittance imaginary part value, two half-power points in the initial frequency sweep interval can be indirectly obtained, and the traditional search method for searching the half-power points is simplified.

And S610, acquiring admittance data of the ultrasonic transducer in a half-power point interval.

Specifically, the driving is performed by using a driving signal with a frequency interval of 1Hz in a half-power point interval, first feedback electrical parameters (such as voltage, current, phase and other data) of the ultrasonic transducer at each frequency point are obtained, and an admittance real part value and an admittance imaginary part value of the ultrasonic transducer in the half-power point interval are calculated.

And S612, fitting an admittance circle according to each admittance real part value and each admittance imaginary part value of the ultrasonic transducer in the half-power point interval, and calculating data such as the circle center, the radius and the like of the admittance circle. Specifically, the least square fitting algorithm can be used for fitting the admittance circle, and the longitudinal coordinate and the radius of the circle center of the admittance circle are calculated.

This application uses the admittance data between the half-power point to carry out admittance circle fitting, has reduced the interference that admittance circle left part probably exists, and the fitting data contain series resonance frequency, and the admittance circle of reconsitution is close to actual working condition, therefore its identification accuracy is higher.

And S614, measuring the parameters of the equivalent circuit model of the ultrasonic transducer. Specifically, the equivalent circuit parameters of the ultrasonic transducer can be calculated according to the following formula, so as to calculate the equivalent circuit model parameters of the ultrasonic transducer, and further obtain the key characteristics such as impedance characteristics and phase characteristics of the ultrasonic transducer as the basis for subsequent driving.

Wherein R is ₁ Is a dynamic resistance value, C ₀ Is a static capacitance value, L ₁ Is a dynamic inductance value, C ₁ Is dynamic capacitance value, r is radius, y is circle center ordinate, f _s Is the series resonance frequency, f ₂ Is the second half power point, f ₁ Is the first half-power point.

After obtaining the parameters of the BVD model of the ultrasonic transducer, the impedance characteristics, the phase characteristics, and the like of the BVD model are obtained through circuit simulation, and the relative error between the measurement result and the true value of the ultrasonic transducer is calculated, where the error condition is as shown in fig. 9. The error comparison of the present application with the conventional method can be shown in table 1.

TABLE 1 error analysis table of identification results of admittance circle fitting method and measurement values of impedance analyzer

The method is based on the equivalent circuit model of the ultrasonic transducer, carries out fast positioning of the sweep frequency interval through a half-power point search algorithm, and carries out admittance circle fitting by using a least square fitting algorithm, thereby accurately identifying the equivalent circuit model parameters of the ultrasonic transducer, and overcoming the defect that the traditional ultrasonic transducer identification algorithm needs a large amount of time. In addition, compared with an empirical approximation method used by a traditional ultrasonic transducer identification algorithm, the theoretical basis of the method is more sufficient, the impedance characteristic, the phase characteristic and the like of the established equivalent circuit model are more in line with the actual driving condition, and the descriptiveness is more sufficient, so that a more accurate basis can be provided for the subsequent driving control of the ultrasonic transducer, and the use efficiency of the ultrasonic transducer is effectively improved.

It should be understood that, although the steps in the flowcharts related to the embodiments as described above are sequentially displayed as indicated by arrows, the steps are not necessarily performed sequentially as indicated by the arrows. The steps are not limited to being performed in the exact order illustrated and, unless explicitly stated herein, may be performed in other orders. Moreover, at least a part of the steps in the flowcharts related to the embodiments described above may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the execution order of the steps or stages is not necessarily sequential, but may be rotated or alternated with other steps or at least a part of the steps or stages in other steps.

Based on the same inventive concept, the embodiment of the application also provides an equivalent parameter measuring device of the ultrasonic transducer, which is used for realizing the equivalent parameter measuring method of the ultrasonic transducer. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the method, so the specific limitations in the embodiment of the equivalent parameter measurement device for one or more ultrasonic transducers provided below can be referred to the limitations on the equivalent parameter measurement method for the ultrasonic transducers, and are not described herein again.

In one embodiment, the application further provides an equivalent parameter measuring device of an ultrasonic transducer, which comprises a driving signal generating circuit and a control circuit which are connected in sequence. The driving signal generating circuit and the control circuit are both used for connecting the ultrasonic transducer.

The driving signal generating circuit is used for outputting a corresponding driving signal to the ultrasonic transducer according to the received frequency control signal and the amplitude control signal;

the control circuit is used for acquiring an initial frequency sweep interval, outputting a corresponding frequency control signal and an amplitude control signal to the driving signal generation circuit according to the initial frequency sweep interval and a first step length so as to sweep the frequency of the ultrasonic transducer in the initial frequency sweep interval by the first step length and acquire a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size;

the control circuit is further used for outputting a corresponding frequency control signal and amplitude control signal to the driving signal generation circuit according to the target frequency sweep interval and the second step length, so that the frequency of the ultrasonic transducer is swept within the target frequency sweep interval by the second step length, and a first feedback electrical parameter set of the ultrasonic transducer is obtained; obtaining equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set; and the target frequency sweeping interval is a frequency band between the first half-power point and the second half-power point.

It can be understood that the specific implementation of the control circuit and the driving signal generating circuit can be determined according to practical situations, and the present application does not limit this specific implementation. In one embodiment, the control circuit may include an acquisition module and a control module, wherein the acquisition module is configured to acquire the first feedback electrical parameter and the second feedback electrical parameter. The control module is configured to perform admittance circle fitting according to the method according to any of the above method embodiments, and determine the first half-power point and the second half-power point according to the second feedback electrical parameter.

In one example, as shown in fig. 10, the driving signal generating circuit may include a DDS, a multiplier, and a power amplifier module, the sampling module may include a sampling resistor, an effective value collecting unit, and a phase locking unit, and the control module includes an MCU and an upper computer. Furthermore, a DSP and an FPGA can be used as the MCU, wherein the model of the DSP is TMS320F28377D, and the DSP can be connected with an upper computer through USB communication. The FPGA model is EP4CE10F17C8, the DDS can be controlled to directly synthesize the driving voltage meeting the preset frequency and size of the upper computer, and an accurate sinusoidal driving signal is provided for the ultrasonic transducer.

In particular, the apparatus shown in fig. 10 may operate according to the following process:

(1) the upper computer sets an initial frequency sweep interval and a frequency sweep driving voltage and sends the initial frequency sweep interval and the frequency sweep driving voltage to the bottom layer driving hardware, so that the bottom layer driving hardware outputs a driving signal according to a preset driving frequency and the driving voltage to drive the ultrasonic transducer. Wherein, the bottom layer driving hardware is DSP and FPGA. In particular, the method of manufacturing a semiconductor device,

(2) and the bottom layer driving hardware captures data such as phases, currents, voltages and the like at two ends of the ultrasonic transducer, feeds the data back to the upper computer, and calculates the admittance imaginary part value of the upper computer. Furthermore, the phase capturing is completed by FPGA according to the zero crossing detection of voltage and current; the voltage and current at two ends of the ultrasonic transducer are converted into direct current through a voltage division circuit (such as a sampling resistor) and an effective value conversion chip in an effective value acquisition unit. And the DSP acquires the target voltage through the 12-bit ADC, and takes the target voltage effective value and the target current effective value after primary mean value filtering and primary median value filtering. The admittance imaginary value can be calculated according to the following formula:

(3) and the upper computer carries out extremum search according to the admittance imaginary value, controls the first step length to be continuously expanded at a rate of 10%, the maximum is 10% of the initial frequency sweep interval, the searched maximum value and the minimum value correspond to two half-power points, and the average value of the corresponding frequencies of the two half-power points is taken as the series resonance frequency. Specifically, the half-power point search algorithm indirectly obtains the half-power point in the sweep frequency interval by searching the maximum value point and the minimum value point of the imaginary part value of the admittance, simplifies the traditional method for searching the maximum value of the real part of the admittance, and can calculate the series resonance frequency by the following formula:

wherein f is _s Is the series resonance frequency, f ₁ Is a first half power point, f ₂ Is the second half-power point.

(4) The voltage, the current and the phase between the two half-power points are used as basic data, and the real admittance part value and the imaginary admittance part value of the ultrasonic transducer in the half-power point interval are calculated and transmitted to an upper computer. Furthermore, the driving voltage with the frequency interval of 1Hz can be used for driving in the half-power point interval, and the data of the voltage, the current, the phase and the like of the ultrasonic transducer in the half-power point interval can be obtained.

(5) And the upper computer performs admittance circle fitting according to the received real admittance part value and imaginary admittance part value, and calculates data such as the circle center, the radius and the like of the admittance circle, so that equivalent circuit model parameters of the ultrasonic transducer are calculated, and key characteristics such as impedance characteristics, phase characteristics and the like of the ultrasonic transducer are further obtained to serve as the basis of subsequent driving. Further, the admittance circle fitting can be performed by using a least two fitting algorithm, and the equivalent parameters of the ultrasonic transducer are calculated according to the following formula:

in one embodiment, as shown in fig. 11, there is provided an equivalent parameter measuring apparatus of an ultrasonic transducer, the apparatus including:

the first feedback electrical parameter set acquisition module is used for sweeping the frequency of the ultrasonic transducer by a second step length in a target frequency sweeping interval so as to acquire a first feedback electrical parameter set of the ultrasonic transducer; the target frequency sweeping interval is a frequency band between the first half-power point and the second half-power point;

and the equivalent parameter acquisition module is used for acquiring equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set.

The modules in the equivalent parameter measuring device of the ultrasonic transducer can be completely or partially realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, there is also provided a controller comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the steps of the above method embodiments when executing the computer program.

In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when being executed by a processor, carries out the steps of the above-mentioned method embodiments.

In an embodiment, a computer program product is provided, comprising a computer program which, when being executed by a processor, carries out the steps of the above-mentioned method embodiments.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, database, or other medium used in the embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high-density embedded nonvolatile Memory, resistive Random Access Memory (ReRAM), Magnetic Random Access Memory (MRAM), Ferroelectric Random Access Memory (FRAM), Phase Change Memory (PCM), graphene Memory, and the like. Volatile Memory can include Random Access Memory (RAM), external cache Memory, and the like. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), among others. The databases referred to in various embodiments provided herein may include at least one of relational and non-relational databases. The non-relational database may include, but is not limited to, a block chain based distributed database, and the like. The processors referred to in the various embodiments provided herein may be, without limitation, general purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, or the like.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A method of measuring equivalent parameters of an ultrasonic transducer, the method comprising:

sweeping the frequency of the ultrasonic transducer by a second step length in a target frequency sweeping interval to obtain a first feedback electrical parameter set of the ultrasonic transducer; the target sweep frequency interval is a frequency band between the first half-power point and the second half-power point; the first feedback electrical parameter set comprises first feedback electrical parameters of the ultrasonic transducer under each target frequency sweeping frequency point, and each target frequency sweeping frequency point is a frequency sweeping frequency point determined according to the target frequency sweeping interval and the second step length;

obtaining equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set; the equivalent parameters comprise a static capacitance value, a dynamic inductance value and a dynamic resistance value;

determining the static capacitance value, the dynamic inductance value, and the dynamic resistance value, respectively, based on the following expressions:

wherein R is ₁ Is the dynamic resistance value, C ₀ Is the static capacitance value, L ₁ Is the dynamic inductance value, C ₁ Is the dynamic capacitance value, r is the radius, y is the longitudinal coordinate of the circle center, f _s For said series resonance frequency, f ₂ Is the second half-power point, f ₁ Is the first half-power point.

2. The method according to claim 1, wherein the step of obtaining the equivalent parameters of the ultrasonic transducer from the first feedback electrical parameter set comprises:

for each target frequency sweeping frequency point, respectively determining an admittance imaginary part value and an admittance real part value of the ultrasonic transducer at the target frequency sweeping frequency point according to the first feedback electrical parameter of the ultrasonic transducer at the target frequency sweeping frequency point;

and fitting an admittance circle according to the admittance imaginary part value and the admittance real part value corresponding to each target frequency sweeping frequency point, and determining the equivalent parameters based on admittance circle parameters obtained by fitting.

3. The method of claim 2, wherein the admittance circle parameters include a center ordinate of an admittance circle and a radius of the admittance circle.

4. The method of claim 2, wherein the second step size is a fixed step size.

5. The method according to any one of claims 2 to 4, wherein the step of performing admittance circle fitting on the imaginary admittance values and the real admittance values corresponding to each of the target swept frequency points comprises:

and processing the admittance imaginary part value and the admittance real part value corresponding to each target frequency sweeping frequency point by adopting a least square fitting algorithm so as to perform admittance circle fitting.

6. The method of claim 1, wherein the step of sweeping the ultrasonic transducer at a first step size within the initial sweep interval to obtain a first half power point and a second half power point of the ultrasonic transducer comprises:

determining each initial frequency sweeping frequency point according to the initial frequency sweeping interval and the first step length;

sweeping the frequency of the ultrasonic transducer based on each initial frequency sweeping frequency point, and acquiring an admittance imaginary part value of the ultrasonic transducer under each initial frequency sweeping frequency point;

determining the initial frequency sweeping frequency point corresponding to the minimum value in each admittance imaginary part value as a first target frequency, and determining the initial frequency sweeping frequency point corresponding to the maximum value in each admittance imaginary part value as a second target frequency;

and determining the smaller value of the first target frequency and the second target frequency as the first half-power point, and determining the larger value of the first target frequency and the second target frequency as the second half-power point.

7. The method according to claim 6, wherein the step of sweeping the ultrasonic transducer based on each initial sweeping frequency point and obtaining admittance imaginary values of the ultrasonic transducer at each initial sweeping frequency point comprises:

sweeping the frequency of the ultrasonic transducer based on each initial frequency sweeping frequency point, and acquiring a second feedback electrical parameter of the ultrasonic transducer under each initial frequency sweeping frequency point; the second feedback electrical parameters comprise an initial voltage effective value, an initial current effective value and a phase of the ultrasonic transducer at a corresponding initial frequency sweeping frequency point;

for each initial frequency sweeping frequency point, filtering the initial voltage effective value to obtain a target voltage effective value, and filtering the initial current effective value to obtain a target current effective value; determining the admittance imaginary part value of the ultrasonic transducer at the initial frequency sweeping frequency point according to the following formula:

wherein, G _img For the value of the imaginary admittance, I _rms Is the effective value of the target current, U _rms And theta is the effective value of the target voltage and is the phase.

8. The method according to claim 6 or 7, wherein the step of determining each initial frequency sweep point according to the initial frequency sweep interval and the first step size comprises:

confirming the first threshold frequency of the initial frequency sweeping interval as a current initial frequency sweeping frequency point;

increasing the first step length according to a preset proportion, and determining a next initial frequency sweeping frequency point according to the increased first step length and the current initial frequency sweeping frequency point;

and taking the next initial frequency sweeping frequency point as the current initial frequency sweeping frequency point, entering a step of increasing the first step length according to a preset proportion, and determining the next initial frequency sweeping frequency point according to the increased first step length and the current initial frequency sweeping frequency point until the next initial frequency sweeping frequency point exceeds the initial frequency sweeping interval, or obtaining the first half-power point and the second half-power point.

9. The method of any one of claims 1 to 4, 6, and 7, further comprising:

acquiring sweep frequency driving voltage; the sweep frequency driving voltage is determined based on the actual driving voltage of the ultrasonic transducer;

sweeping the ultrasonic transducer by a first step size within the initial sweep interval, comprising:

sweeping the ultrasonic transducer by a first step length within the initial sweep interval based on the sweep driving voltage;

sweeping the ultrasonic transducer by a second step length within a target sweep interval, comprising:

and based on the sweep frequency driving voltage, sweeping the frequency of the ultrasonic transducer by a second step length in a target sweep frequency interval.

10. A measuring device based on the equivalent parameter measuring method of the ultrasonic transducer according to any one of claims 1 to 9, wherein the device comprises a driving signal generating circuit and a control circuit which are connected in sequence, and the driving signal generating circuit and the control circuit are both used for connecting the ultrasonic transducer;

the driving signal generating circuit is used for outputting a corresponding driving signal to the ultrasonic transducer according to the received frequency control signal and amplitude control signal;

the control circuit is used for acquiring an initial frequency sweep interval, outputting a corresponding frequency control signal and an amplitude control signal to the driving signal generation circuit according to the initial frequency sweep interval and a first step length, so as to sweep the frequency of the ultrasonic transducer in the initial frequency sweep interval by the first step length and acquire a first half-power point and a second half-power point of the ultrasonic transducer; wherein the first step size is an incremental step size;

the control circuit is further used for outputting a corresponding frequency control signal and amplitude control signal to the driving signal generation circuit according to a target frequency sweep interval and a second step length, so that the frequency of the ultrasonic transducer is swept within the target frequency sweep interval by the second step length, and a first feedback electrical parameter set of the ultrasonic transducer is obtained; obtaining equivalent parameters of the ultrasonic transducer according to the first feedback electrical parameter set; and the target sweep frequency interval is a frequency band between the first half-power point and the second half-power point.